(maint) Remove rc_mocks from build_defaults

Packaging internals have been updated to no longer require rc_mocks, so this
commit removes the rc_mocks from the build_defaults.
(maint) Add f18 mocks to build_defaults

Fedora 18 has been released to the world, so we should build packages for it.
This commit adds the fedora 18 mocks to the build_defaults so we can easily
supply fedora 18 packages.
(maint) Update debian changelog template

This commit updates the debian changelog template to remove EOL ubuntu releases
and add the newest ubuntu release, quantal.
Merge pull request #416 from haus/remove_rc_mocks

Packaging updates